This invention relates generally to tray stacking wires as utilized generally with corrugated paperboard trays and the like. More particularly, the invention related to a unitary tray stacking wire with greatly enhanced assembly features with respect to the trays used therewith.
The prior art includes several types of tray stacking wires. U.S. Pat. No. 2,944,722 to Dahlhauser et al describes a stacking wire of the general type in which the wire is inserted upwardly through an aperture in the sidewall of a tray, with inwardly extending tips at the bottom ends of the stacking wire fitting into corresponding holes in the sidewall of the tray.
U.S. Pat. No. 3,750,936 to Crane describes a stacking wire for top insertion into a conventional corrugated paperboard container having a double wall construction. After insertion and upon lifting to a vertical position, the feet of the wire with abbreviated sharp prongs having sharp ends, bite into the container wall and become engaged therewith. However, a number of bends are necessary to prevent the sharp ends of the wire feet from penetrating through the sidewall of the container or tray.
U.S. Pat. No. 3,106,332 to Dieguez describes, in relevant part, a stacking wire quite similar to that of Crane. It operates in substantially the same way and similarly requires abbreviated sheared sharp prongs on its feet.
In summary, with respect to the prior art, a number of difficulties are encountered with respect to the several types of constructions available. Some stacking wires are adapted to be engaged in customized die cut slits of a cross or star shape in the top edge of a double wall in the tray as opposed to being adapted for engagement in an elongated slot aperture standard to the industry. However, when die cut hole slits are used, the lead ends of the mating wire must be manually sprung outwardly beyond the universal slot aperture, thereby resulting in more labor time for location and insertion than when using an open slot aperture. With respect to those stacking wires adapted for use with open slot apertures, the prior art constructions suffer from an undue number of multiple or compound bends plus reverse bends or loops. In addition, it is not uncommon for such wires to be easily knocked out of vertical orientation--resulting in a considerable disruption of the stacking function. In addition, those stacking wires having sheared sharp wire ends tend to easily penetrate the wall of a corrugated paperboard tray, at the same time endangering personnel during the handling and installation thereof. With respect to stacking wires which are inserted upwardly through a tray wall through a slot in the bottom edge thereof, the primary drawback associated therewith resides in the fact that assembly is very slow and the tray must be tipped or hung over a flat surface in order to obtain access to the open slot in the bottom edge of the tray wall one end of the tray at a time. Furthermore, the bottom feet of the stacking wire may catch on a floor or truckbed, for example, on which the trays are placed.